Levings Application 1 Flashcards
1
Q
MHC protein numbers (2)
A
- humans have 6 different genes encoding MHC proteins, with 2 copies of each gene
- total of 12 copies
2
Q
MHC class I (2)
A
- 3 MHC class I proteins
- HLA-A, HLA-B, and HLA-C
3
Q
HLA
A
- human leukocyte antigen
4
Q
MHC class II (2)
A
- 3 MHC class II proteins
- HLA-DP, HLA-DQ, HLA-DR
5
Q
how are MHC proteins key for diversity (3)
A
- many different alleles for each MHC gene
- polymorphism maximizes probability of binding to peptides from pathogens
- particular combination of 12 HLAs we each express defines our tissue type
6
Q
MHC diversity and transplantation
A
- MHC diversity is why transplanted cells/organs are recognized as non-self
7
Q
what is the mouse version of the human HLA complex
A
- mouse H-2 complex
8
Q
allorecognition
A
- the ability of an individual organism to distinguish its own tissues from those of another
9
Q
allorecognition pathways (3)
A
- direct pathway
- indirect pathway
- semidirect pathway
10
Q
what percentage of recipient T cells participate in direct pathway allorecognition
A
- 1-7% of T cells participate in direct recognition for any given donor/host pair depending on degree of donor mismatch
11
Q
allorecognition: direct pathway
A
- donor APC presents MHC-donor antigen complex to the TCR of a recipient T cell
12
Q
allorecognition: direct presentation steps (2)
A
- donor-derived DCs leave the graft, migrate to LNs, and stimulate naive alloantigen-specific T cells
- activated T cells traffic to graft where they can be restimulated by donor cells expressing MHC and initiate an immune response
13
Q
which form of presentation is important in early allograft responses
A
- direct pathway
14
Q
allorecognition: indirection pathway
A
- transplanted antigens are processed and presented on recipient MHC from recipient APC to a recipient T cell
15
Q
allorecognition: semidirect pathway
A
- transplanted MHC-donor antigen are presented by a recipient APC to a recipient T cells